If I simple copy 'config.php' from old version to 1.2.0.5 I see the error in my browser:

*******Fatal error: Class 'LDAPServers' not found in /var/www/phpldapadmin-1.2.0.5/config/config.php on line 158*******

and if I use config from new version (1.2.0.5) I see similar messages:

*******Automatically removed objectClass from template Courier Mail: Alias: courierMailAlias removed from template as it is not defined in the schema Automatically removed objectClass from template Samba: Group Mapping: sambaGroupMapping removed from template as it is not defined in the schema******... when I login into phpLdapAdmin and start to work with objects.

So, I believe, that config files of version 1.2 and 1.1 are not such similar as it said in manual. May be I wrong?